OneSteel says desal plant won't harm Gulf

OneSteel at Whyalla says its 1.5-gigalitre desalination plant will have no impact on salinity in the upper Spencer Gulf in South Australia.

The steelworks will start constructing the plant within weeks.

It says desalinated water will replace just over 20 per cent of the seven gigalitres of Murray supplies it draws on annually.

OneSteel chief executive Mark Parry says unlike proposals from other companies to build 100-gigalitre plants in the Gulf, the only effects on the environment from its project will be positive.

"It's very important to us that, one, as I said we reduce our reliance on the Murray given environmental concerns, but also we ensure that we've got sufficient water to manage and ramp up our operations in the future," he said.

He says the brine discharge will be filtered and diluted before being put back into the sea.

"It's very low volumes comparatively compared to BHP Billiton [desalination plan] and the other salt water that we put back into the system," he said.

"We've been fully informing the community via the environmental consultative group.

"We've had our own environmental studies done and we're very satisfied we will have negligible impact on the Gulf due to our discharge."